Spin-orbit coupled bosons in one dimension: emergent gauge field and Lifshitz transition

TL;DR

This paper investigates a quantum phase transition in one-dimensional spinor Bose liquids with spin-orbit coupling, revealing an emergent gauge field and Lifshitz transition with novel critical exponents, relevant for ultracold atom experiments.

Contribution

It uncovers a new type of Lifshitz transition with an emergent gauge field in 1D spinor Bose liquids, providing critical exponents from numerical simulations and linking to ultracold atom systems.

Findings

Identified a Lifshitz transition with dynamical exponent z ≈ 2.

Discovered an emergent dynamical gauge field at the transition.

Extracted new critical exponents for the fixed point.

Abstract

In the presence of strong spin-independent interactions and spin-orbit coupling, we show that the spinor Bose liquid confined to one spatial dimension undergoes an interaction- or density-tuned quantum phase transition similar to one theoretically proposed for itinerant magnetic solid-state systems. The order parameter describes broken $Z_2$ inversion symmetry, with the ordered phase accompanied by non-vanishing momentum which is generated by fluctuations of an emergent dynamical gauge field at the phase transition. This quantum phase transition has dynamical critical exponent $z \simeq 2$, typical of a Lifshitz transition, but is described by a nontrivial interacting fixed point. From direct numerical simulation of the microscopic model, we extract previously unknown critical exponents for this fixed point. Our model describes a realistic situation of 1D ultracold atoms with Raman-induced spin-orbit coupling, establishing this system as a platform for studying exotic critical behavior of the Hertz-Millis type.